Extracts the integration test part of build.yml into a reusable workflow called testing.yml.
This workflow now also explicitly requires an existing SSH connection to be alive (a socket at the ControlPath of the SSH config) in order to run tests on the DRAC clusters
Also adds a new full_cluster_tests.yml workflow that is run periodically (once a week) and runs the integration tests on all slurm clusters (not just 'mila', as in build.yml).
build.ymlinto a reusable workflow calledtesting.yml.full_cluster_tests.ymlworkflow that is run periodically (once a week) and runs the integration tests on all slurm clusters (not just'mila', as inbuild.yml).